It's a moot point... We're saying the same thing. Sure they could, if they wanted to immediately tank their business. You could set your house on fire. What's your point?
The point is you can have a valuable business without having any presence on Apple stores to begin with. If you disagree with that, well you’re just wrong.
We're not talking about a fart app. We're talking about multi-billion dollar businesses that have been entrenched in App Store for a decade. Exiting that market isn't an option. If it was an option they would have done it.
Will they? Probably not because people with Apple devices tend to spend more money.